1. Field of the Invention
This invention relates to a and vulcanization mold for the production of laminated bodies, especially shaped shoe soles, from several layers of different and/or differently colored rubber or plastic, which mold includes several superimposed, shaped, mold cavities for preshaping the individual layers and which are separated from one another by intermediate plates removable from the vulcanization mold in order to unite the preshaped layers.
2. Description of the Prior Art
From German AS No. 1236771, a vulcanization mold for the production of a structured heel from rubber or an equivalent raw material, the heel having a heel-tap made from a rubber which is different as compared to the rubber of the heel, is known. The mold consists of a lower mold, a middle mold having a chamber for the heel and an upper mold, and a moveable intermediate plate which can be inserted loosely between the middle mold and the lower mold having a chamber for the heel-tap. With this vulcanization mold, blanks of different working material are molded simultaneously under pressure and temperature and are prevulcanized and are thereafter united following removal of the intermediate plate and are fully cured under pressure and temperature into a laminated body. Additionally, a vulcanization mold has been proposed for the production of elastic bottom parts of shoes of two layers of different composition. The layers are prefabricated in nests of molds separated from one another by an intermediate plate and are hardened together after removal of the intermediate plate, the flat, intermediate plate being developed more thinly at one end corresponding to the angle of deviation running differently from the plane of the mold separation.
With such molding tools for vulcanization, however, only layers with flat, i.e., planar contact, or interfacial, surfaces can be joined because of the shaping of the intermediate plate as a plate of essentially constant thickness, but not layers where the interfacial surfaces between the different working materials run in spatial separating surfaces deviating from the plane.
For the production of laminated bodies, especially of multilayered rubber molded soles, it is also known to harden individual layers in separate individual molds and then to join these layers in a common mold, possibly with the aid of an adhesive. This method however must be carried out in steps requiring much labor and is too expensive, therefore, for large scale production. Additionally, the joining together of the layers by means of adhesives creates ugly and poor transition areas between the layers which increases the quota of rejects, and the correction of which (transition areas) requires an expensive mechanical, secondary processing. Moreover, the bonded areas are endangered insofar as they can separate under load.
The present invention is based on the object of developing a form of vulcanization such that the production of laminated bodies from different work materials is made possible, the interfacial surfaces of which run in planes deviating from one another, or are non-planar. With this method of vulcanization, it is to be possible to manufacture laminated bodies of more than two layers on a large scale with a small technical and apparatus expenditure. There should be the possibility for interfacial surfaces on opposing sides of the middle layer to deviate from one another. It is an object to provide a vulcanization mold with which it is possible to produce multilayered molded soles, wherein the individual layers are developed with perfect transition areas.